酸性环境抑制CIK细胞对肝癌HepG2细胞的杀伤活性

目的 研究酸性环境对CIK（cytokine-induced killer, CIK）细胞杀伤肝癌HepG2细胞的影响。方法 利用IFN-γ、IL-2及CD3抗体诱导外周血单个核细胞获得CIK细胞。在pH6.5及pH7.4条件下将CIK细胞和荧光素酶标记的HepG2细胞（HepG2-luc）按不同的效靶比混合培养，用小动物活体成像系统检测HepG2-luc荧光强度并计算杀伤活性，用MTT法检测并计算杀伤活性。在pH6.5及pH7.4条件下，在含CIK条件培养液0、50%和100%的情况下培养HepG2细胞，流式细胞仪检测凋亡坏死的细胞比例。结果 pH7.4时CIK细胞对HepG2细胞的杀伤率明显高于pH6.5时。CIK条件培养液作用下，pH7.4时HepG2细胞的凋亡坏死比例明显高于pH6.5。结论 酸性环境明显抑制了CIK细胞对肝癌细胞HepG2的杀伤活性。

Inhibition Effect of Acid Environment on Cytotoxicity of Cytokine-induced Killer Cells Against Hepatocellular Carcinoma Cells HepG2

Objective To investigate the effect of acid environment on the cytotoxicity of cytokine-induced killer(CIK) cells against hepatocellular carcinoma cells HepG2. Methods CIK cells were induced from peripheral blood mononuclear cells with IFN-γ, IL-2 and CD3 mAb. HepG2 cells and luciferase marked HepG2 cells (HepG2-luc) were co-cultured with CIK cells at different effect/target ratios, and the medium were adjusted at pH6.5 and pH7.4 respectively. The luciferase intensity of HepG2-luc was detected with IVIS Spectrum System, and the cytotoxicity was calculated according to luciferase intensity and MTT assay. HepG2 cells were cultured with the medium including 0, 50% and 100% CIK at pH6.5 and pH7.4 respectively. The apoptosis and necrotic cells percentage were detected by flow cytometry. Results The cytotoxicity of CIK cells at pH7.4 were significantly higher than that at pH6.5. Also, in CIK condition medium, the percentage of apoptosis and necrotic HepG2 cells at pH7.4 condition was significantly higher than that at pH6.5. Conclusion Acid environment markedly inhibits the cytotoxicity of CIK cells against hepatocellular carcinoma cells HepG2.